| // Copyright 2011 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #include "v8.h" |
| |
| #include "scopes.h" |
| |
| #include "bootstrapper.h" |
| #include "compiler.h" |
| #include "scopeinfo.h" |
| |
| #include "allocation-inl.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| // ---------------------------------------------------------------------------- |
| // A Zone allocator for use with LocalsMap. |
| |
| // TODO(isolates): It is probably worth it to change the Allocator class to |
| // take a pointer to an isolate. |
| class ZoneAllocator: public Allocator { |
| public: |
| /* nothing to do */ |
| virtual ~ZoneAllocator() {} |
| |
| virtual void* New(size_t size) { return ZONE->New(static_cast<int>(size)); } |
| |
| /* ignored - Zone is freed in one fell swoop */ |
| virtual void Delete(void* p) {} |
| }; |
| |
| |
| static ZoneAllocator LocalsMapAllocator; |
| |
| |
| // ---------------------------------------------------------------------------- |
| // Implementation of LocalsMap |
| // |
| // Note: We are storing the handle locations as key values in the hash map. |
| // When inserting a new variable via Declare(), we rely on the fact that |
| // the handle location remains alive for the duration of that variable |
| // use. Because a Variable holding a handle with the same location exists |
| // this is ensured. |
| |
| static bool Match(void* key1, void* key2) { |
| String* name1 = *reinterpret_cast<String**>(key1); |
| String* name2 = *reinterpret_cast<String**>(key2); |
| ASSERT(name1->IsSymbol()); |
| ASSERT(name2->IsSymbol()); |
| return name1 == name2; |
| } |
| |
| |
| VariableMap::VariableMap() : HashMap(Match, &LocalsMapAllocator, 8) {} |
| VariableMap::~VariableMap() {} |
| |
| |
| Variable* VariableMap::Declare( |
| Scope* scope, |
| Handle<String> name, |
| VariableMode mode, |
| bool is_valid_lhs, |
| Variable::Kind kind, |
| InitializationFlag initialization_flag) { |
| HashMap::Entry* p = HashMap::Lookup(name.location(), name->Hash(), true); |
| if (p->value == NULL) { |
| // The variable has not been declared yet -> insert it. |
| ASSERT(p->key == name.location()); |
| p->value = new Variable(scope, |
| name, |
| mode, |
| is_valid_lhs, |
| kind, |
| initialization_flag); |
| } |
| return reinterpret_cast<Variable*>(p->value); |
| } |
| |
| |
| Variable* VariableMap::Lookup(Handle<String> name) { |
| HashMap::Entry* p = HashMap::Lookup(name.location(), name->Hash(), false); |
| if (p != NULL) { |
| ASSERT(*reinterpret_cast<String**>(p->key) == *name); |
| ASSERT(p->value != NULL); |
| return reinterpret_cast<Variable*>(p->value); |
| } |
| return NULL; |
| } |
| |
| |
| // ---------------------------------------------------------------------------- |
| // Implementation of Scope |
| |
| Scope::Scope(Scope* outer_scope, ScopeType type) |
| : isolate_(Isolate::Current()), |
| inner_scopes_(4), |
| variables_(), |
| temps_(4), |
| params_(4), |
| unresolved_(16), |
| decls_(4), |
| already_resolved_(false) { |
| SetDefaults(type, outer_scope, Handle<ScopeInfo>::null()); |
| // At some point we might want to provide outer scopes to |
| // eval scopes (by walking the stack and reading the scope info). |
| // In that case, the ASSERT below needs to be adjusted. |
| ASSERT((type == GLOBAL_SCOPE || type == EVAL_SCOPE) == (outer_scope == NULL)); |
| ASSERT(!HasIllegalRedeclaration()); |
| } |
| |
| |
| Scope::Scope(Scope* inner_scope, |
| ScopeType type, |
| Handle<ScopeInfo> scope_info) |
| : isolate_(Isolate::Current()), |
| inner_scopes_(4), |
| variables_(), |
| temps_(4), |
| params_(4), |
| unresolved_(16), |
| decls_(4), |
| already_resolved_(true) { |
| SetDefaults(type, NULL, scope_info); |
| if (!scope_info.is_null()) { |
| num_heap_slots_ = scope_info_->ContextLength(); |
| } |
| AddInnerScope(inner_scope); |
| } |
| |
| |
| Scope::Scope(Scope* inner_scope, Handle<String> catch_variable_name) |
| : isolate_(Isolate::Current()), |
| inner_scopes_(1), |
| variables_(), |
| temps_(0), |
| params_(0), |
| unresolved_(0), |
| decls_(0), |
| already_resolved_(true) { |
| SetDefaults(CATCH_SCOPE, NULL, Handle<ScopeInfo>::null()); |
| AddInnerScope(inner_scope); |
| ++num_var_or_const_; |
| Variable* variable = variables_.Declare(this, |
| catch_variable_name, |
| VAR, |
| true, // Valid left-hand side. |
| Variable::NORMAL, |
| kCreatedInitialized); |
| AllocateHeapSlot(variable); |
| } |
| |
| |
| void Scope::SetDefaults(ScopeType type, |
| Scope* outer_scope, |
| Handle<ScopeInfo> scope_info) { |
| outer_scope_ = outer_scope; |
| type_ = type; |
| scope_name_ = isolate_->factory()->empty_symbol(); |
| dynamics_ = NULL; |
| receiver_ = NULL; |
| function_ = NULL; |
| arguments_ = NULL; |
| illegal_redecl_ = NULL; |
| scope_inside_with_ = false; |
| scope_contains_with_ = false; |
| scope_calls_eval_ = false; |
| // Inherit the strict mode from the parent scope. |
| strict_mode_flag_ = (outer_scope != NULL) |
| ? outer_scope->strict_mode_flag_ : kNonStrictMode; |
| outer_scope_calls_non_strict_eval_ = false; |
| inner_scope_calls_eval_ = false; |
| force_eager_compilation_ = false; |
| num_var_or_const_ = 0; |
| num_stack_slots_ = 0; |
| num_heap_slots_ = 0; |
| scope_info_ = scope_info; |
| start_position_ = RelocInfo::kNoPosition; |
| end_position_ = RelocInfo::kNoPosition; |
| } |
| |
| |
| Scope* Scope::DeserializeScopeChain(CompilationInfo* info, |
| Scope* global_scope) { |
| // Reconstruct the outer scope chain from a closure's context chain. |
| ASSERT(!info->closure().is_null()); |
| Context* context = info->closure()->context(); |
| Scope* current_scope = NULL; |
| Scope* innermost_scope = NULL; |
| bool contains_with = false; |
| while (!context->IsGlobalContext()) { |
| if (context->IsWithContext()) { |
| Scope* with_scope = new Scope(current_scope, |
| WITH_SCOPE, |
| Handle<ScopeInfo>::null()); |
| current_scope = with_scope; |
| // All the inner scopes are inside a with. |
| contains_with = true; |
| for (Scope* s = innermost_scope; s != NULL; s = s->outer_scope()) { |
| s->scope_inside_with_ = true; |
| } |
| } else if (context->IsFunctionContext()) { |
| ScopeInfo* scope_info = context->closure()->shared()->scope_info(); |
| current_scope = new Scope(current_scope, |
| FUNCTION_SCOPE, |
| Handle<ScopeInfo>(scope_info)); |
| } else if (context->IsBlockContext()) { |
| ScopeInfo* scope_info = ScopeInfo::cast(context->extension()); |
| current_scope = new Scope(current_scope, |
| BLOCK_SCOPE, |
| Handle<ScopeInfo>(scope_info)); |
| } else { |
| ASSERT(context->IsCatchContext()); |
| String* name = String::cast(context->extension()); |
| current_scope = new Scope(current_scope, Handle<String>(name)); |
| } |
| if (contains_with) current_scope->RecordWithStatement(); |
| if (innermost_scope == NULL) innermost_scope = current_scope; |
| |
| // Forget about a with when we move to a context for a different function. |
| if (context->previous()->closure() != context->closure()) { |
| contains_with = false; |
| } |
| context = context->previous(); |
| } |
| |
| global_scope->AddInnerScope(current_scope); |
| return (innermost_scope == NULL) ? global_scope : innermost_scope; |
| } |
| |
| |
| bool Scope::Analyze(CompilationInfo* info) { |
| ASSERT(info->function() != NULL); |
| Scope* top = info->function()->scope(); |
| |
| while (top->outer_scope() != NULL) top = top->outer_scope(); |
| top->AllocateVariables(info->calling_context()); |
| |
| #ifdef DEBUG |
| if (info->isolate()->bootstrapper()->IsActive() |
| ? FLAG_print_builtin_scopes |
| : FLAG_print_scopes) { |
| info->function()->scope()->Print(); |
| } |
| #endif |
| |
| info->SetScope(info->function()->scope()); |
| return true; // Can not fail. |
| } |
| |
| |
| void Scope::Initialize() { |
| ASSERT(!already_resolved()); |
| |
| // Add this scope as a new inner scope of the outer scope. |
| if (outer_scope_ != NULL) { |
| outer_scope_->inner_scopes_.Add(this); |
| scope_inside_with_ = outer_scope_->scope_inside_with_ || is_with_scope(); |
| } else { |
| scope_inside_with_ = is_with_scope(); |
| } |
| |
| // Declare convenience variables. |
| // Declare and allocate receiver (even for the global scope, and even |
| // if naccesses_ == 0). |
| // NOTE: When loading parameters in the global scope, we must take |
| // care not to access them as properties of the global object, but |
| // instead load them directly from the stack. Currently, the only |
| // such parameter is 'this' which is passed on the stack when |
| // invoking scripts |
| if (is_declaration_scope()) { |
| Variable* var = |
| variables_.Declare(this, |
| isolate_->factory()->this_symbol(), |
| VAR, |
| false, |
| Variable::THIS, |
| kCreatedInitialized); |
| var->AllocateTo(Variable::PARAMETER, -1); |
| receiver_ = var; |
| } else { |
| ASSERT(outer_scope() != NULL); |
| receiver_ = outer_scope()->receiver(); |
| } |
| |
| if (is_function_scope()) { |
| // Declare 'arguments' variable which exists in all functions. |
| // Note that it might never be accessed, in which case it won't be |
| // allocated during variable allocation. |
| variables_.Declare(this, |
| isolate_->factory()->arguments_symbol(), |
| VAR, |
| true, |
| Variable::ARGUMENTS, |
| kCreatedInitialized); |
| } |
| } |
| |
| |
| Scope* Scope::FinalizeBlockScope() { |
| ASSERT(is_block_scope()); |
| ASSERT(temps_.is_empty()); |
| ASSERT(params_.is_empty()); |
| |
| if (num_var_or_const() > 0) return this; |
| |
| // Remove this scope from outer scope. |
| for (int i = 0; i < outer_scope_->inner_scopes_.length(); i++) { |
| if (outer_scope_->inner_scopes_[i] == this) { |
| outer_scope_->inner_scopes_.Remove(i); |
| break; |
| } |
| } |
| |
| // Reparent inner scopes. |
| for (int i = 0; i < inner_scopes_.length(); i++) { |
| outer_scope()->AddInnerScope(inner_scopes_[i]); |
| } |
| |
| // Move unresolved variables |
| for (int i = 0; i < unresolved_.length(); i++) { |
| outer_scope()->unresolved_.Add(unresolved_[i]); |
| } |
| |
| return NULL; |
| } |
| |
| |
| Variable* Scope::LocalLookup(Handle<String> name) { |
| Variable* result = variables_.Lookup(name); |
| if (result != NULL || scope_info_.is_null()) { |
| return result; |
| } |
| // If we have a serialized scope info, we might find the variable there. |
| // |
| // We should never lookup 'arguments' in this scope as it is implicitly |
| // present in every scope. |
| ASSERT(*name != *isolate_->factory()->arguments_symbol()); |
| // There should be no local slot with the given name. |
| ASSERT(scope_info_->StackSlotIndex(*name) < 0); |
| |
| // Check context slot lookup. |
| VariableMode mode; |
| InitializationFlag init_flag; |
| int index = scope_info_->ContextSlotIndex(*name, &mode, &init_flag); |
| if (index < 0) { |
| // Check parameters. |
| mode = VAR; |
| init_flag = kCreatedInitialized; |
| index = scope_info_->ParameterIndex(*name); |
| if (index < 0) { |
| // Check the function name. |
| index = scope_info_->FunctionContextSlotIndex(*name, &mode); |
| if (index < 0) return NULL; |
| } |
| } |
| |
| Variable* var = |
| variables_.Declare(this, |
| name, |
| mode, |
| true, |
| Variable::NORMAL, |
| init_flag); |
| var->AllocateTo(Variable::CONTEXT, index); |
| return var; |
| } |
| |
| |
| Variable* Scope::Lookup(Handle<String> name) { |
| for (Scope* scope = this; |
| scope != NULL; |
| scope = scope->outer_scope()) { |
| Variable* var = scope->LocalLookup(name); |
| if (var != NULL) return var; |
| } |
| return NULL; |
| } |
| |
| |
| Variable* Scope::DeclareFunctionVar(Handle<String> name, VariableMode mode) { |
| ASSERT(is_function_scope() && function_ == NULL); |
| Variable* function_var = new Variable( |
| this, name, mode, true, Variable::NORMAL, kCreatedInitialized); |
| function_ = new(isolate_->zone()) VariableProxy(isolate_, function_var); |
| return function_var; |
| } |
| |
| |
| void Scope::DeclareParameter(Handle<String> name, VariableMode mode) { |
| ASSERT(!already_resolved()); |
| ASSERT(is_function_scope()); |
| Variable* var = variables_.Declare( |
| this, name, mode, true, Variable::NORMAL, kCreatedInitialized); |
| params_.Add(var); |
| } |
| |
| |
| Variable* Scope::DeclareLocal(Handle<String> name, |
| VariableMode mode, |
| InitializationFlag init_flag) { |
| ASSERT(!already_resolved()); |
| // This function handles VAR and CONST modes. DYNAMIC variables are |
| // introduces during variable allocation, INTERNAL variables are allocated |
| // explicitly, and TEMPORARY variables are allocated via NewTemporary(). |
| ASSERT(mode == VAR || |
| mode == CONST || |
| mode == CONST_HARMONY || |
| mode == LET); |
| ++num_var_or_const_; |
| return |
| variables_.Declare(this, name, mode, true, Variable::NORMAL, init_flag); |
| } |
| |
| |
| Variable* Scope::DeclareGlobal(Handle<String> name) { |
| ASSERT(is_global_scope()); |
| return variables_.Declare(this, |
| name, |
| DYNAMIC_GLOBAL, |
| true, |
| Variable::NORMAL, |
| kCreatedInitialized); |
| } |
| |
| |
| VariableProxy* Scope::NewUnresolved(Handle<String> name, int position) { |
| // Note that we must not share the unresolved variables with |
| // the same name because they may be removed selectively via |
| // RemoveUnresolved(). |
| ASSERT(!already_resolved()); |
| VariableProxy* proxy = new(isolate_->zone()) VariableProxy( |
| isolate_, name, false, position); |
| unresolved_.Add(proxy); |
| return proxy; |
| } |
| |
| |
| void Scope::RemoveUnresolved(VariableProxy* var) { |
| // Most likely (always?) any variable we want to remove |
| // was just added before, so we search backwards. |
| for (int i = unresolved_.length(); i-- > 0;) { |
| if (unresolved_[i] == var) { |
| unresolved_.Remove(i); |
| return; |
| } |
| } |
| } |
| |
| |
| Variable* Scope::NewTemporary(Handle<String> name) { |
| ASSERT(!already_resolved()); |
| Variable* var = new Variable(this, |
| name, |
| TEMPORARY, |
| true, |
| Variable::NORMAL, |
| kCreatedInitialized); |
| temps_.Add(var); |
| return var; |
| } |
| |
| |
| void Scope::AddDeclaration(Declaration* declaration) { |
| decls_.Add(declaration); |
| } |
| |
| |
| void Scope::SetIllegalRedeclaration(Expression* expression) { |
| // Record only the first illegal redeclaration. |
| if (!HasIllegalRedeclaration()) { |
| illegal_redecl_ = expression; |
| } |
| ASSERT(HasIllegalRedeclaration()); |
| } |
| |
| |
| void Scope::VisitIllegalRedeclaration(AstVisitor* visitor) { |
| ASSERT(HasIllegalRedeclaration()); |
| illegal_redecl_->Accept(visitor); |
| } |
| |
| |
| Declaration* Scope::CheckConflictingVarDeclarations() { |
| int length = decls_.length(); |
| for (int i = 0; i < length; i++) { |
| Declaration* decl = decls_[i]; |
| if (decl->mode() != VAR) continue; |
| Handle<String> name = decl->proxy()->name(); |
| |
| // Iterate through all scopes until and including the declaration scope. |
| Scope* previous = NULL; |
| Scope* current = decl->scope(); |
| do { |
| // There is a conflict if there exists a non-VAR binding. |
| Variable* other_var = current->variables_.Lookup(name); |
| if (other_var != NULL && other_var->mode() != VAR) { |
| return decl; |
| } |
| previous = current; |
| current = current->outer_scope_; |
| } while (!previous->is_declaration_scope()); |
| } |
| return NULL; |
| } |
| |
| |
| void Scope::CollectStackAndContextLocals(ZoneList<Variable*>* stack_locals, |
| ZoneList<Variable*>* context_locals) { |
| ASSERT(stack_locals != NULL); |
| ASSERT(context_locals != NULL); |
| |
| // Collect temporaries which are always allocated on the stack. |
| for (int i = 0; i < temps_.length(); i++) { |
| Variable* var = temps_[i]; |
| if (var->is_used()) { |
| ASSERT(var->IsStackLocal()); |
| stack_locals->Add(var); |
| } |
| } |
| |
| // Collect declared local variables. |
| for (VariableMap::Entry* p = variables_.Start(); |
| p != NULL; |
| p = variables_.Next(p)) { |
| Variable* var = reinterpret_cast<Variable*>(p->value); |
| if (var->is_used()) { |
| if (var->IsStackLocal()) { |
| stack_locals->Add(var); |
| } else if (var->IsContextSlot()) { |
| context_locals->Add(var); |
| } |
| } |
| } |
| } |
| |
| |
| void Scope::AllocateVariables(Handle<Context> context) { |
| ASSERT(outer_scope_ == NULL); // eval or global scopes only |
| |
| // 1) Propagate scope information. |
| // If we are in an eval scope, we may have other outer scopes about |
| // which we don't know anything at this point. Thus we must be conservative |
| // and assume they may invoke eval themselves. Eventually we could capture |
| // this information in the ScopeInfo and then use it here (by traversing |
| // the call chain stack, at compile time). |
| |
| bool outer_scope_calls_non_strict_eval = false; |
| if (!is_global_scope()) { |
| context->ComputeEvalScopeInfo(&outer_scope_calls_non_strict_eval); |
| } |
| PropagateScopeInfo(outer_scope_calls_non_strict_eval); |
| |
| // 2) Resolve variables. |
| Scope* global_scope = NULL; |
| if (is_global_scope()) global_scope = this; |
| ResolveVariablesRecursively(global_scope, context); |
| |
| // 3) Allocate variables. |
| AllocateVariablesRecursively(); |
| } |
| |
| |
| bool Scope::AllowsLazyCompilation() const { |
| return !force_eager_compilation_ && HasTrivialOuterContext(); |
| } |
| |
| |
| bool Scope::HasTrivialContext() const { |
| // A function scope has a trivial context if it always is the global |
| // context. We iteratively scan out the context chain to see if |
| // there is anything that makes this scope non-trivial; otherwise we |
| // return true. |
| for (const Scope* scope = this; scope != NULL; scope = scope->outer_scope_) { |
| if (scope->is_eval_scope()) return false; |
| if (scope->scope_inside_with_) return false; |
| if (scope->num_heap_slots_ > 0) return false; |
| } |
| return true; |
| } |
| |
| |
| bool Scope::HasTrivialOuterContext() const { |
| Scope* outer = outer_scope_; |
| if (outer == NULL) return true; |
| // Note that the outer context may be trivial in general, but the current |
| // scope may be inside a 'with' statement in which case the outer context |
| // for this scope is not trivial. |
| return !scope_inside_with_ && outer->HasTrivialContext(); |
| } |
| |
| |
| int Scope::ContextChainLength(Scope* scope) { |
| int n = 0; |
| for (Scope* s = this; s != scope; s = s->outer_scope_) { |
| ASSERT(s != NULL); // scope must be in the scope chain |
| if (s->num_heap_slots() > 0) n++; |
| } |
| return n; |
| } |
| |
| |
| Scope* Scope::DeclarationScope() { |
| Scope* scope = this; |
| while (!scope->is_declaration_scope()) { |
| scope = scope->outer_scope(); |
| } |
| return scope; |
| } |
| |
| |
| Handle<ScopeInfo> Scope::GetScopeInfo() { |
| if (scope_info_.is_null()) { |
| scope_info_ = ScopeInfo::Create(this); |
| } |
| return scope_info_; |
| } |
| |
| |
| void Scope::GetNestedScopeChain( |
| List<Handle<ScopeInfo> >* chain, |
| int position) { |
| chain->Add(Handle<ScopeInfo>(GetScopeInfo())); |
| |
| for (int i = 0; i < inner_scopes_.length(); i++) { |
| Scope* scope = inner_scopes_[i]; |
| int beg_pos = scope->start_position(); |
| int end_pos = scope->end_position(); |
| ASSERT(beg_pos >= 0 && end_pos >= 0); |
| if (beg_pos <= position && position <= end_pos) { |
| scope->GetNestedScopeChain(chain, position); |
| return; |
| } |
| } |
| } |
| |
| |
| #ifdef DEBUG |
| static const char* Header(ScopeType type) { |
| switch (type) { |
| case EVAL_SCOPE: return "eval"; |
| case FUNCTION_SCOPE: return "function"; |
| case GLOBAL_SCOPE: return "global"; |
| case CATCH_SCOPE: return "catch"; |
| case BLOCK_SCOPE: return "block"; |
| case WITH_SCOPE: return "with"; |
| } |
| UNREACHABLE(); |
| return NULL; |
| } |
| |
| |
| static void Indent(int n, const char* str) { |
| PrintF("%*s%s", n, "", str); |
| } |
| |
| |
| static void PrintName(Handle<String> name) { |
| SmartArrayPointer<char> s = name->ToCString(DISALLOW_NULLS); |
| PrintF("%s", *s); |
| } |
| |
| |
| static void PrintLocation(Variable* var) { |
| switch (var->location()) { |
| case Variable::UNALLOCATED: |
| break; |
| case Variable::PARAMETER: |
| PrintF("parameter[%d]", var->index()); |
| break; |
| case Variable::LOCAL: |
| PrintF("local[%d]", var->index()); |
| break; |
| case Variable::CONTEXT: |
| PrintF("context[%d]", var->index()); |
| break; |
| case Variable::LOOKUP: |
| PrintF("lookup"); |
| break; |
| } |
| } |
| |
| |
| static void PrintVar(int indent, Variable* var) { |
| if (var->is_used() || !var->IsUnallocated()) { |
| Indent(indent, Variable::Mode2String(var->mode())); |
| PrintF(" "); |
| PrintName(var->name()); |
| PrintF("; // "); |
| PrintLocation(var); |
| if (var->has_forced_context_allocation()) { |
| if (!var->IsUnallocated()) PrintF(", "); |
| PrintF("forced context allocation"); |
| } |
| PrintF("\n"); |
| } |
| } |
| |
| |
| static void PrintMap(int indent, VariableMap* map) { |
| for (VariableMap::Entry* p = map->Start(); p != NULL; p = map->Next(p)) { |
| Variable* var = reinterpret_cast<Variable*>(p->value); |
| PrintVar(indent, var); |
| } |
| } |
| |
| |
| void Scope::Print(int n) { |
| int n0 = (n > 0 ? n : 0); |
| int n1 = n0 + 2; // indentation |
| |
| // Print header. |
| Indent(n0, Header(type_)); |
| if (scope_name_->length() > 0) { |
| PrintF(" "); |
| PrintName(scope_name_); |
| } |
| |
| // Print parameters, if any. |
| if (is_function_scope()) { |
| PrintF(" ("); |
| for (int i = 0; i < params_.length(); i++) { |
| if (i > 0) PrintF(", "); |
| PrintName(params_[i]->name()); |
| } |
| PrintF(")"); |
| } |
| |
| PrintF(" {\n"); |
| |
| // Function name, if any (named function literals, only). |
| if (function_ != NULL) { |
| Indent(n1, "// (local) function name: "); |
| PrintName(function_->name()); |
| PrintF("\n"); |
| } |
| |
| // Scope info. |
| if (HasTrivialOuterContext()) { |
| Indent(n1, "// scope has trivial outer context\n"); |
| } |
| if (is_strict_mode()) Indent(n1, "// strict mode scope\n"); |
| if (scope_inside_with_) Indent(n1, "// scope inside 'with'\n"); |
| if (scope_contains_with_) Indent(n1, "// scope contains 'with'\n"); |
| if (scope_calls_eval_) Indent(n1, "// scope calls 'eval'\n"); |
| if (outer_scope_calls_non_strict_eval_) { |
| Indent(n1, "// outer scope calls 'eval' in non-strict context\n"); |
| } |
| if (inner_scope_calls_eval_) Indent(n1, "// inner scope calls 'eval'\n"); |
| if (num_stack_slots_ > 0) { Indent(n1, "// "); |
| PrintF("%d stack slots\n", num_stack_slots_); } |
| if (num_heap_slots_ > 0) { Indent(n1, "// "); |
| PrintF("%d heap slots\n", num_heap_slots_); } |
| |
| // Print locals. |
| Indent(n1, "// function var\n"); |
| if (function_ != NULL) { |
| PrintVar(n1, function_->var()); |
| } |
| |
| Indent(n1, "// temporary vars\n"); |
| for (int i = 0; i < temps_.length(); i++) { |
| PrintVar(n1, temps_[i]); |
| } |
| |
| Indent(n1, "// local vars\n"); |
| PrintMap(n1, &variables_); |
| |
| Indent(n1, "// dynamic vars\n"); |
| if (dynamics_ != NULL) { |
| PrintMap(n1, dynamics_->GetMap(DYNAMIC)); |
| PrintMap(n1, dynamics_->GetMap(DYNAMIC_LOCAL)); |
| PrintMap(n1, dynamics_->GetMap(DYNAMIC_GLOBAL)); |
| } |
| |
| // Print inner scopes (disable by providing negative n). |
| if (n >= 0) { |
| for (int i = 0; i < inner_scopes_.length(); i++) { |
| PrintF("\n"); |
| inner_scopes_[i]->Print(n1); |
| } |
| } |
| |
| Indent(n0, "}\n"); |
| } |
| #endif // DEBUG |
| |
| |
| Variable* Scope::NonLocal(Handle<String> name, VariableMode mode) { |
| if (dynamics_ == NULL) dynamics_ = new DynamicScopePart(); |
| VariableMap* map = dynamics_->GetMap(mode); |
| Variable* var = map->Lookup(name); |
| if (var == NULL) { |
| // Declare a new non-local. |
| InitializationFlag init_flag = (mode == VAR) |
| ? kCreatedInitialized : kNeedsInitialization; |
| var = map->Declare(NULL, |
| name, |
| mode, |
| true, |
| Variable::NORMAL, |
| init_flag); |
| // Allocate it by giving it a dynamic lookup. |
| var->AllocateTo(Variable::LOOKUP, -1); |
| } |
| return var; |
| } |
| |
| |
| Variable* Scope::LookupRecursive(Handle<String> name, |
| Handle<Context> context, |
| BindingKind* binding_kind) { |
| ASSERT(binding_kind != NULL); |
| // Try to find the variable in this scope. |
| Variable* var = LocalLookup(name); |
| |
| // We found a variable and we are done. (Even if there is an 'eval' in |
| // this scope which introduces the same variable again, the resulting |
| // variable remains the same.) |
| if (var != NULL) { |
| *binding_kind = BOUND; |
| return var; |
| } |
| |
| // We did not find a variable locally. Check against the function variable, |
| // if any. We can do this for all scopes, since the function variable is |
| // only present - if at all - for function scopes. |
| // |
| // This lookup corresponds to a lookup in the "intermediate" scope sitting |
| // between this scope and the outer scope. (ECMA-262, 3rd., requires that |
| // the name of named function literal is kept in an intermediate scope |
| // in between this scope and the next outer scope.) |
| *binding_kind = UNBOUND; |
| if (function_ != NULL && function_->name().is_identical_to(name)) { |
| var = function_->var(); |
| *binding_kind = BOUND; |
| } else if (outer_scope_ != NULL) { |
| var = outer_scope_->LookupRecursive(name, context, binding_kind); |
| if (*binding_kind == BOUND && (is_function_scope() || is_with_scope())) { |
| var->ForceContextAllocation(); |
| } |
| } |
| |
| if (is_with_scope()) { |
| // The current scope is a with scope, so the variable binding can not be |
| // statically resolved. However, note that it was necessary to do a lookup |
| // in the outer scope anyway, because if a binding exists in an outer scope, |
| // the associated variable has to be marked as potentially being accessed |
| // from inside of an inner with scope (the property may not be in the 'with' |
| // object). |
| *binding_kind = DYNAMIC_LOOKUP; |
| return NULL; |
| } else if (is_eval_scope()) { |
| // No local binding was found, no 'with' statements have been encountered |
| // and the code is executed as part of a call to 'eval'. The calling context |
| // contains scope information that we can use to determine if the variable |
| // is global, i.e. the calling context chain does not contain a binding and |
| // no 'with' contexts. |
| ASSERT(*binding_kind == UNBOUND); |
| *binding_kind = context->GlobalIfNotShadowedByEval(name) |
| ? UNBOUND_EVAL_SHADOWED : DYNAMIC_LOOKUP; |
| return NULL; |
| } else if (calls_non_strict_eval()) { |
| // A variable binding may have been found in an outer scope, but the current |
| // scope makes a non-strict 'eval' call, so the found variable may not be |
| // the correct one (the 'eval' may introduce a binding with the same name). |
| // In that case, change the lookup result to reflect this situation. |
| if (*binding_kind == BOUND) { |
| *binding_kind = BOUND_EVAL_SHADOWED; |
| } else if (*binding_kind == UNBOUND) { |
| *binding_kind = UNBOUND_EVAL_SHADOWED; |
| } |
| } |
| return var; |
| } |
| |
| |
| void Scope::ResolveVariable(Scope* global_scope, |
| Handle<Context> context, |
| VariableProxy* proxy) { |
| ASSERT(global_scope == NULL || global_scope->is_global_scope()); |
| |
| // If the proxy is already resolved there's nothing to do |
| // (functions and consts may be resolved by the parser). |
| if (proxy->var() != NULL) return; |
| |
| // Otherwise, try to resolve the variable. |
| BindingKind binding_kind; |
| Variable* var = LookupRecursive(proxy->name(), context, &binding_kind); |
| switch (binding_kind) { |
| case BOUND: |
| // We found a variable binding. |
| break; |
| |
| case BOUND_EVAL_SHADOWED: |
| // We found a variable variable binding that might be shadowed |
| // by 'eval' introduced variable bindings. |
| if (var->is_global()) { |
| var = NonLocal(proxy->name(), DYNAMIC_GLOBAL); |
| } else { |
| Variable* invalidated = var; |
| var = NonLocal(proxy->name(), DYNAMIC_LOCAL); |
| var->set_local_if_not_shadowed(invalidated); |
| } |
| break; |
| |
| case UNBOUND: |
| // No binding has been found. Declare a variable in global scope. |
| ASSERT(global_scope != NULL); |
| var = global_scope->DeclareGlobal(proxy->name()); |
| break; |
| |
| case UNBOUND_EVAL_SHADOWED: |
| // No binding has been found. But some scope makes a |
| // non-strict 'eval' call. |
| var = NonLocal(proxy->name(), DYNAMIC_GLOBAL); |
| break; |
| |
| case DYNAMIC_LOOKUP: |
| // The variable could not be resolved statically. |
| var = NonLocal(proxy->name(), DYNAMIC); |
| break; |
| } |
| |
| ASSERT(var != NULL); |
| proxy->BindTo(var); |
| } |
| |
| |
| void Scope::ResolveVariablesRecursively(Scope* global_scope, |
| Handle<Context> context) { |
| ASSERT(global_scope == NULL || global_scope->is_global_scope()); |
| |
| // Resolve unresolved variables for this scope. |
| for (int i = 0; i < unresolved_.length(); i++) { |
| ResolveVariable(global_scope, context, unresolved_[i]); |
| } |
| |
| // Resolve unresolved variables for inner scopes. |
| for (int i = 0; i < inner_scopes_.length(); i++) { |
| inner_scopes_[i]->ResolveVariablesRecursively(global_scope, context); |
| } |
| } |
| |
| |
| bool Scope::PropagateScopeInfo(bool outer_scope_calls_non_strict_eval ) { |
| if (outer_scope_calls_non_strict_eval) { |
| outer_scope_calls_non_strict_eval_ = true; |
| } |
| |
| bool calls_non_strict_eval = |
| (scope_calls_eval_ && !is_strict_mode()) || |
| outer_scope_calls_non_strict_eval_; |
| for (int i = 0; i < inner_scopes_.length(); i++) { |
| Scope* inner_scope = inner_scopes_[i]; |
| if (inner_scope->PropagateScopeInfo(calls_non_strict_eval)) { |
| inner_scope_calls_eval_ = true; |
| } |
| if (inner_scope->force_eager_compilation_) { |
| force_eager_compilation_ = true; |
| } |
| } |
| |
| return scope_calls_eval_ || inner_scope_calls_eval_; |
| } |
| |
| |
| bool Scope::MustAllocate(Variable* var) { |
| // Give var a read/write use if there is a chance it might be accessed |
| // via an eval() call. This is only possible if the variable has a |
| // visible name. |
| if ((var->is_this() || var->name()->length() > 0) && |
| (var->has_forced_context_allocation() || |
| scope_calls_eval_ || |
| inner_scope_calls_eval_ || |
| scope_contains_with_ || |
| is_catch_scope() || |
| is_block_scope())) { |
| var->set_is_used(true); |
| } |
| // Global variables do not need to be allocated. |
| return !var->is_global() && var->is_used(); |
| } |
| |
| |
| bool Scope::MustAllocateInContext(Variable* var) { |
| // If var is accessed from an inner scope, or if there is a possibility |
| // that it might be accessed from the current or an inner scope (through |
| // an eval() call or a runtime with lookup), it must be allocated in the |
| // context. |
| // |
| // Exceptions: temporary variables are never allocated in a context; |
| // catch-bound variables are always allocated in a context. |
| if (var->mode() == TEMPORARY) return false; |
| if (is_catch_scope() || is_block_scope()) return true; |
| return var->has_forced_context_allocation() || |
| scope_calls_eval_ || |
| inner_scope_calls_eval_ || |
| scope_contains_with_ || |
| var->is_global(); |
| } |
| |
| |
| bool Scope::HasArgumentsParameter() { |
| for (int i = 0; i < params_.length(); i++) { |
| if (params_[i]->name().is_identical_to( |
| isolate_->factory()->arguments_symbol())) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| |
| void Scope::AllocateStackSlot(Variable* var) { |
| var->AllocateTo(Variable::LOCAL, num_stack_slots_++); |
| } |
| |
| |
| void Scope::AllocateHeapSlot(Variable* var) { |
| var->AllocateTo(Variable::CONTEXT, num_heap_slots_++); |
| } |
| |
| |
| void Scope::AllocateParameterLocals() { |
| ASSERT(is_function_scope()); |
| Variable* arguments = LocalLookup(isolate_->factory()->arguments_symbol()); |
| ASSERT(arguments != NULL); // functions have 'arguments' declared implicitly |
| |
| bool uses_nonstrict_arguments = false; |
| |
| if (MustAllocate(arguments) && !HasArgumentsParameter()) { |
| // 'arguments' is used. Unless there is also a parameter called |
| // 'arguments', we must be conservative and allocate all parameters to |
| // the context assuming they will be captured by the arguments object. |
| // If we have a parameter named 'arguments', a (new) value is always |
| // assigned to it via the function invocation. Then 'arguments' denotes |
| // that specific parameter value and cannot be used to access the |
| // parameters, which is why we don't need to allocate an arguments |
| // object in that case. |
| |
| // We are using 'arguments'. Tell the code generator that is needs to |
| // allocate the arguments object by setting 'arguments_'. |
| arguments_ = arguments; |
| |
| // In strict mode 'arguments' does not alias formal parameters. |
| // Therefore in strict mode we allocate parameters as if 'arguments' |
| // were not used. |
| uses_nonstrict_arguments = !is_strict_mode(); |
| } |
| |
| // The same parameter may occur multiple times in the parameters_ list. |
| // If it does, and if it is not copied into the context object, it must |
| // receive the highest parameter index for that parameter; thus iteration |
| // order is relevant! |
| for (int i = params_.length() - 1; i >= 0; --i) { |
| Variable* var = params_[i]; |
| ASSERT(var->scope() == this); |
| if (uses_nonstrict_arguments) { |
| // Force context allocation of the parameter. |
| var->ForceContextAllocation(); |
| } |
| |
| if (MustAllocate(var)) { |
| if (MustAllocateInContext(var)) { |
| ASSERT(var->IsUnallocated() || var->IsContextSlot()); |
| if (var->IsUnallocated()) { |
| AllocateHeapSlot(var); |
| } |
| } else { |
| ASSERT(var->IsUnallocated() || var->IsParameter()); |
| if (var->IsUnallocated()) { |
| var->AllocateTo(Variable::PARAMETER, i); |
| } |
| } |
| } |
| } |
| } |
| |
| |
| void Scope::AllocateNonParameterLocal(Variable* var) { |
| ASSERT(var->scope() == this); |
| ASSERT(!var->IsVariable(isolate_->factory()->result_symbol()) || |
| !var->IsStackLocal()); |
| if (var->IsUnallocated() && MustAllocate(var)) { |
| if (MustAllocateInContext(var)) { |
| AllocateHeapSlot(var); |
| } else { |
| AllocateStackSlot(var); |
| } |
| } |
| } |
| |
| |
| void Scope::AllocateNonParameterLocals() { |
| // All variables that have no rewrite yet are non-parameter locals. |
| for (int i = 0; i < temps_.length(); i++) { |
| AllocateNonParameterLocal(temps_[i]); |
| } |
| |
| for (VariableMap::Entry* p = variables_.Start(); |
| p != NULL; |
| p = variables_.Next(p)) { |
| Variable* var = reinterpret_cast<Variable*>(p->value); |
| AllocateNonParameterLocal(var); |
| } |
| |
| // For now, function_ must be allocated at the very end. If it gets |
| // allocated in the context, it must be the last slot in the context, |
| // because of the current ScopeInfo implementation (see |
| // ScopeInfo::ScopeInfo(FunctionScope* scope) constructor). |
| if (function_ != NULL) { |
| AllocateNonParameterLocal(function_->var()); |
| } |
| } |
| |
| |
| void Scope::AllocateVariablesRecursively() { |
| // Allocate variables for inner scopes. |
| for (int i = 0; i < inner_scopes_.length(); i++) { |
| inner_scopes_[i]->AllocateVariablesRecursively(); |
| } |
| |
| // If scope is already resolved, we still need to allocate |
| // variables in inner scopes which might not had been resolved yet. |
| if (already_resolved()) return; |
| // The number of slots required for variables. |
| num_stack_slots_ = 0; |
| num_heap_slots_ = Context::MIN_CONTEXT_SLOTS; |
| |
| // Allocate variables for this scope. |
| // Parameters must be allocated first, if any. |
| if (is_function_scope()) AllocateParameterLocals(); |
| AllocateNonParameterLocals(); |
| |
| // Force allocation of a context for this scope if necessary. For a 'with' |
| // scope and for a function scope that makes an 'eval' call we need a context, |
| // even if no local variables were statically allocated in the scope. |
| bool must_have_context = is_with_scope() || |
| (is_function_scope() && calls_eval()); |
| |
| // If we didn't allocate any locals in the local context, then we only |
| // need the minimal number of slots if we must have a context. |
| if (num_heap_slots_ == Context::MIN_CONTEXT_SLOTS && !must_have_context) { |
| num_heap_slots_ = 0; |
| } |
| |
| // Allocation done. |
| ASSERT(num_heap_slots_ == 0 || num_heap_slots_ >= Context::MIN_CONTEXT_SLOTS); |
| } |
| |
| |
| int Scope::StackLocalCount() const { |
| return num_stack_slots() - |
| (function_ != NULL && function_->var()->IsStackLocal() ? 1 : 0); |
| } |
| |
| |
| int Scope::ContextLocalCount() const { |
| if (num_heap_slots() == 0) return 0; |
| return num_heap_slots() - Context::MIN_CONTEXT_SLOTS - |
| (function_ != NULL && function_->var()->IsContextSlot() ? 1 : 0); |
| } |
| |
| } } // namespace v8::internal |